Hi,
On 9/14/23 03:05, Wu, Wentong wrote:
>> From: Oliver Neukum <oneukum@xxxxxxxx>
>>
>> On 13.09.23 03:40, Wentong Wu wrote:
>>
>>> +struct ljca_bank_descriptor {
>>> + u8 bank_id;
>>> + u8 pin_num;
>>> +
>>> + /* 1 bit for each gpio, 1 means valid */
>>> + u32 valid_pins;
>>
>> No endianness?
>
> On both sides, the endianness is same.
Right, but normally USB drivers are also written so that they can work on big-endian CPUs.
I realize that this driver will likely never be used with a big-endian CPU but still it is good practice to make the driver work on big-endian CPUs too. Even if it is just to set a good example when other drivers copy the code.
So this should be:
struct ljca_bank_descriptor {
u8 bank_id;
u8 pin_num;
/* 1 bit for each gpio, 1 means valid */
__le32 valid_pins;
} __packed;
And then when reading valid_pins you should use:
u32 valid_pins = get_unaligned_le32(&ljca_bank_descriptor.valid_pins);
On x86_64 the compiler should optimize all of this away to
just a regular read.
Regards,
Hans
